This invention relates to methods and apparatus for accessing the pericardial space for medical treatment of the heart.
Knowledge of the pericardium dates back to the time of Galen (129-200 A.D.) the Greek physician and anatomist who gave the pericardium its name. The pericardial sac surrounds the heart like a glove enfolds a hand, and the pericardial space is naturally fluid-filled. The normal pericardium functions to prevent dilatation of the chambers of the heart, lubricates the surfaces of the heart, and maintains the heart in a fixed geometric position. It also provides a barrier to the spread of infection from adjacent structures in the chest, and prevents the adhesion of surrounding tissues to the heart. See generally, Holt J P: The normal pericardium, Amer J Cardiol 26:455,1970; Spodick D H: Medical history of the pericardium, Amer J Cardiol 26:447,1970. The normal pericardial space is small in volume and the fluid film within it is too thin to functionally separate the heart from the pericardium. It has been observed that when fluid is injected into the pericardial space it accumulates in the atrioventricular and interventricular grooves, but not over the ventricular surfaces [Shabetai R: Pericardial and cardiac pressure, Circulation 77:1, 1988].
Pericardiocentesis, or puncture of the pericardium, heretofore has been indicated for (1) diagnosis of pericardial disease(s) by study of the pericardial fluid, (2) withdrawal of pericardial fluid for the treatment of acute cardiac tamponade, and (3) infusion of therapeutic agents for the treatment of malignant effusion or tumors. During 1994, it is estimated that approximately 12,000 pericardiocentesis procedures were performed in the United States and that less than 200 of these patients underwent therapy with the intrapericardial injection of drugs. At present, intrapericardial injection of drugs is clinically limited to the treatment of abnormal pericardial conditions and diseases, such as malignant or loculated pericardial effusions and tumors. Drugs that have been injected into the pericardial space include antibiotic (sclerosing) agents [Wei J, et al: Recurrent cardiac tamponade and large pericardial effusions: Management with an indwelling pericardial catheter, Amer J Cardiol 42:281,1978; Davis S, et al: Intrapericardial tetracycline for the management of cardiac tamponade secondary to malignant pericardial effusion, N Engl J Med 299:1113,1978; Sheperd F, et al: Tetracycline sclerosis in the management of malignant pericardial effusion, J Clin Oncol 3:1678,1985; Maher E, et al: Intraperi-cardial instillation of bleomycin in malignant pericardial effusion, Amer Heart J 11:613,1986; van der Gaast A, et al: Intrapericardial instillation of bleomycin in management of malignant pericardial effusion, Eur J Cancer Clin Oncol 25:1505,1989; Imamura T, et al: Intrapericardial instillation of OK-432 for the management of malignant pericardial effusion, Jpn J Med 28:62,1989; Cormican M, et al: Intraperi-cardial bleomycin for the management of cardiac tamponade secondary to malignant pericardial effusion, Brit Heart J 63:61,1990; Mitchell M, et al: Multiple myeloma complicated by restrictive cardiomyopathy and cardiac tamponade, Chest 103:946, 1993], antineoplastic drugs [Terpenning M, et al: Intrapericardial nitrogen mustard with catheter drainage for the treatment of malignant effusions, Proc Amer Assoc Cancer Res (abstr) 20:286,1979; Markman M, et al: Intrapericardial instillation of cisplatin in a patient with a large malignant effusion, Cancer Drug Delivery 1:49,1985; Figoli F, et al: Pharmacokinetics of VM 26 given intrapericardially or intravenously in patients with malignant pericardial effusion, Cancer Chemotherapy Pharmacol 20:239, 1987; Fiorentino M, et al: Intrapericardial instillation of platin in malignant peri-cardial effusion, Cancer 62:1904,1988], radioactive compound [Martini N, et al: Intra-pericardial instillation of radioactive chronic phosphate in malignant pericardial effusion, AJR 128:639,1977], and a fibrinolytic agent [Cross J, et al: Use of streptokinase to aid in drainage of postoperative pericardial effusion, Brit Heart J 62:217,1989].
Intrapericardial drug delivery has not been clinically utilized for heart-specific treatments where pericardial pathology is normal, because the pericardial space is normally small and very difficult to access without invasive surgery or risk of cardiac injury by standard needle pericardiocentesis techniques. The pericardiocentesis procedure is carried out by experienced personnel in the cardiac catheterization laboratory, with equipment for fluoroscopy and monitoring of the electrocardiogram. Electrocardiographic monitoring of the procedure using the pericardial needle as an electrode is commonly employed [Bishop L H, et al: The electrocardiogram as a safeguard in pericardiocentesis, JAMA 162:264,1956; Neill J R, et al: A pericardiocentesis electrode N Engl J Med 264:711,1961; Gotsman M S, et al: A pericardiocentesis electrode needle, Br Heart J 28:566,1966; Kerber R E, et al: Electrocardiographic indications of atrial puncture during pericardiocentesis, N Engl J Med 282:1142,1970]. An echocardiographic transducer with a central lumen has also been used to guide the pericardiocentesis needle [Goldberg B B, et al: Ultrasonically guided pericardiocentesis, Amer J Cardiol 31:490,1973]. Complications associated with needle pericardiocentesis include laceration of a coronary artery or the right ventricle, perforation of the right atrium or ventricle, puncture of the stomach or colon, pneumothorax, arrhythmia, tamponade, hypotension, ventricular fibrillation, and death. The complication rates for needle pericardiocentesis are increased in situations where the pericardial space and fluid effusion volume is small (i.e., the pericardial size is more like normal).
Chin et al have described a method and apparatus for accessing the pericardial space for the insertion of implantable defibrillation leads [U.S. Pat. No. 5,071,428]. The method required gripping the pericardium with a forceps device and cutting the pericardium with a scalpel (pericardiotomy) under direct vision through a subxiphoid surgical incision.
A method for the intrapericardial injection of angiogenic agents has been reported [Uchida Y, et al: Angiogenic therapy of acute myocardial infarction by intrapericardial injection of basic fibroblast growth factor and heparan sulfate, Circulation AHA Abstracts--1994]. While the method was not described in detail, it generally involved the percutaneous transcatheter bolus injection of drugs into the pericardial cavity via the right atrium. The major limitation of this method is that the right atrial wall is crossed which could lead to bleeding into the pericardial space. In addition, the method involved the bolus injection of drugs rather than long-term delivery via a catheter or controlled release material.